TSB 09-05-00

THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN 09-06-99, DATED SEP. 10,
1999, WHICH SHOULD BE REMOVED FROM YOUR FILES. THIS IS A COMPLETE REVISION AND
NO ASTERISKS HAVE BEEN USED TO HIGHLIGHT REVISIONS.

THIS APPLIES ONLY A VEHICLE EQUIPPED WITH 3.9L, 5.2L or 5.9L GAS ENGINE.

Discussion:

This bulletin involves the replacement of the engine intake manifold plenum
pan gasket.

Symptom/Condition:
An engine intake manifold plenum pan gasket oil leak may occur on some V-6 and
V-8 style engines. The oil leak is internal to the engine so no external oil
leakage will be present. Two symptoms of this oil leak condition may be present.
The vehicle operator may experience an engine spark knock during acceleration
and/or an increase in the amount of engine oil consumed by the engine.

Diagnosis:
Make sure Technical Service Bulletin (TSB) 18-48-98 has been performed.

NOTE: IT IS IMPORTANT THAT THE COIL AND SPARK PLUG WIRES ARE ROUTED EXACTLY
AS SPECIFIED IN TSB 18-48-98 TO ACHIEVE THE MOST BENEFIT.

Inspect the Positive Crankcase Ventilation (PCV) valve. Shake the PCV valve
to verify that the pintle inside of the PCV valve is free. Replace the PVC if
the pintle is not free.

If the intake manifold plenum pan gasket is leaking, an additional vacuum source
will be created inside of the engine at the location of the pan gasket leakage.-
Engine combustion blow-by gases, oil vapor, and air from the crankcase filter/breather
may be drawn past the leaking pan gasket and into the intake manifold. In most
cases when this condition occurs, an engine at idle will create the highest
vacuum and lowest amount of engine blow-by.

1. Allow the engine to reach normal operating temperature.

2. Stop the engine.

3. Disconnect the breather hose from the air cleaner.

4. Attach a vacuum I pressure gauge to the end of the breather
hose (Figure 1).

NOTE: DURING THIS DIAGNOSIS, IT WOULD BE NORMAL FOR THE ENGINE
TO DEVELOP PRESSURE WITHIN THE ENGINE CRANKCASE. THIS IS DUE TO -THE NORMAL
PROCESS OF. EXHAUST BLOW-BY- GASES- LEAKING PAST THE ENGINE PISTON RINGS AND
ACCUMULATING IN THE ENGINE CRANKCASE. DO NOT ALLOW MORE THAN 3 PSI (20.7 kPa)
OF PRESSURE TO BUILD WITHIN THE ENGINE WHEN PERFORMING THE FOLLOWING DIAGNOSTIC
PROCEDURE.

8. Start the warmed engine and observe the vacuum gauge.

9. Allow the engine to idle for approximately 30 seconds.
Do not allow more than 3psi (20.7 kPa) of pressure to develop in the engine
crankcase.

10. If the attached vacuum I pressure gauge does not indicate that
a vacuum is present in the engine crankcase, then the intake manifold plenum
pan gasket is good and no further internal engine vacuum leak diagnosis is required.

11. If an internal vacuum leak is present then perform the Repair
Procedure.

*NOTE: the part numbers are continually being
revised. Use the most recent part numbers from the dealership computer if you
perform this repair yourself.

Repair Procedure:
1. Refer to the appropriate year Service Manual, Section 9:
ENGINE for removal and installation instructions.

NOTE: CLEAN ALL OIL RESIDUE FROM THE INTERIOR SURFACES OF THE PLENUM PAN AND
THE INTAKE MANIFOLD PLENUM CHAMBER.

NOTE: THE PROPER BOLT TORQUE AND TIGHTENING SEQUENCE IS CRITICAL AND MUST BE
FOLLOWED WHEN TIGHTENING BOTH THE PLENUM PAN BOLTS AND THE INTAKE MANIFOLD FLANGE
BOLTS.

3.9L Bolt Tightening Sequence and Torque Procedure:

3.9L Plenum Pan Bolt Torque Procedure

STEP

WHICH BOLT

TORQUE

1

All Bolts

5.4 Nm (48 in. lbs.)

2

All Bolts

9.5 Nm (84 in. lbs.)

3

Check All Bolts

9.5 NM (84 in. lbs.)

3.9L Intake Manifold Flange Bolt Torque Procedure

STEP

WHICH BOLT

TORQUE

1

1 and 2

1.4 NM (12 in. lbs.)

2

1 and 2

2.7 NM (24 in. lbs.)

3

1 and 2

4.1 NM (36 in. lbs.)

4

1 and 2

5.4 NM (48 in. lbs.)

5

1 and 2

6.7 NM (60 in. lbs.)

6

1 and 2

8.1 NM (72 in. lbs.)

7

3 through 12

8.1 NM (72 in. lbs.)

8

Check All Bolts

8.1 NM (72 in. lbs.)

9

All Bolts

16.3 NM (12 ft. lbs.)

10

Check All Bolts

16.3 NM (12 ft. lbs.)

5.2L/5.9L Bolt Tightening Sequence and
Torque Procedure:

5.2L / 5.9L Plenum Pan Bolt Torque Procedure

STEP

WHICH BOLT

TORQUE

1

All Bolts

5.4 NM (48 in. lbs.)

2

All Bolts

9.5 NM (84 in. lbs.)

3

Check All Bolts

9.5 NM (84 in. lbs.)

5.2L / 5.9L Intake Manifold Flange Bolt Torque Procedure

STEP

WHICH BOLT

TORQUE

1

1 and 4*

1.4 NM (12 in. lbs.)

2

1 and 4*

2.7 NM (24 in. lbs.)

3

1 and 4*

4.1 NM (36 in. lbs.)

4

1 and 4*

5.4 NM (48 in. lbs.)

5

1 and 4*

6.7 NM (60 in. lbs.)

6

1 and 4*

8.1 NM (72 in. lbs.)

7

5 through 12

8.1 NM (72 in. lbs.)

8

Check All Bolts

8.1 NM (72 in. lbs.)

9

All Bolts

16.3 NM (12 ft. lbs.)

10

Check All Bolts

16.3 NM (12 ft. lbs.)

* The bulletin clearly says to tighten bolts 1
and 4, but this is probably a typo because the service manual says to
tighten bolts 1 through 4, and nowhere in the TSB
does it say to tighten bolts 2 and 3, which would only be tightened to 12 ft.
lbs when you reach step 9.

2. With the engine reassembled, inspect the coil and spark
plug wires for proper routing. Refer to TSB 09-48-98 for additional assistance.

3. Start the engine and allow it to warm to normal engine
operating temperature.

NOTE: ALLOW THE COMBUSTION CHAMBER CLEANER TO SOAK INSIDE OF THE ENGINE FOR
2 TO 2.5 HOURS. NOTE: A SECOND APPLICATION OF THE COMBUSTION CHAMBER CONDITIONER
MAY BE REQUIRED IF THERE WAS A LARGE QUANTITY OF OIL LEAKAGE PAST THE INTAKE
PLENUM PAN GASKET.